| 摘要 |
1,118,474. Frequency discriminators. ROLLS-ROYCE Ltd. 1 June, 1967, No. 25307/67. Heading H3A. [Also in Division G1] Periodic variations in the pulse rate of a pulse train having a constant average frequency are detected by comparing the pulse rate with that of a train of clock pulses, to produce an output signal if consecutively the clock pulse rate exceeds the varying pulse rate and the varying pulse rate exceeds the clock pulse rate. Assume initially bi-stable circuits 60, 110 are in their " 1 " state, then the next clock pulse switches bi-stable circuit 60 to its " 0 " state. The next pulse on input 32 switches bi-stable circuit 60 back to its " 1 " state, and is also fed via AND gate 54 to one input 68 of AND gate 70. The other input 66 still receives a " 0 " due to delay 64, so that no signal is passed to counter 102. Subsequent pulses at 32 have no effect on bistable circuit 60, but they pass through AND gates 54, 70 and are counted in counter 102 until the next clock pulse switches bi-stable circuit 60 into its " 0 " state and closes gate 70. The above procedure is repeated until the counter 102 reaches a predetermined count and switches bi-stable circuit 110 to its " 0 " state, resetting the counter. Gate 80 is now enabled, and the roles of the clock pulses and the other pulses are reversed, with the counter counting the number of clock pulses occurring between pulses at input 32. The input signal applied to 32 is derived from a scintillation counter positioned near a rotary bearing which includes a radioactive roller, Fig. 1 (not shown). |
